The unique problem of growing single crystal from a melt involves the selective growth of a single or dominate growth direction from a number of possible paths. The current state of the art for the growth of a single crystal for metals includes the floating zone process, the Czochralski process, and the Bridgman method. These methods require a seed or template crystal with the same composition as the desired sample or the use of a crucible to contain the melted sample, which may introduce contamination or reaction with the melt.
Other methods disclose producing a single crystal without the use of a seed crystal. For example, U.S. Pat. No. 7,175,705 to Fujimura et al. discloses a process to produce a semiconductor single crystal without the use of a seed crystal. Fujimura, however, requires that solid raw material be left in the raw material disposed in the crucible to promote nucleation and therefore, prevent the raw material melt from being supercooled in order to produce a single crystal. The disadvantage to Fujimura is that the use of a solid material left in the raw material leads to waste and, thus, is more costly.
Another method, such as the one disclosed in U.S. Pat. No. 6,153,007 to Nakata discloses a method of producing a single crystal without the use of a seed crystal. Nakata, however, requires that the method be performed under micro-gravitational conditions, which are achieved in space stations, space shuttles, rockets and aircraft. Thus, Nakata requires simulations of micro-gravitational conditions, which requires additional equipment and, thus, an increase in cost, in order to produce a single crystal without the use of a seed crystal.